Polybenzimidazole compounds, polymeric media, and methods of post-polymerization modifications

Abstract

A PBI compound includes imidazole nitrogens at least a portion of which are substituted with a moiety containing a carbonyl group, the substituted imidazole nitrogens being bonded to carbon of the carbonyl group. At least 85% of the nitrogens may be substituted. The carbonyl-containing moiety may include RCO—, where R is alkoxy or haloalkyl. The PBI compound may exhibit a first temperature marking an onset of weight loss corresponding to reversion of the substituted PBI that is less than a second temperature marking an onset of decomposition of an otherwise identical PBI compound without the substituted moiety. The PBI compound may be included in separatory media. A substituted PBI synthesis method may include providing a parent PBI in a less than 5 wt % solvent solution. Substituting may use more than 5 equivalents in relation to the imidazole nitrogens to be substituted.

1. A substituted PBI synthesis method comprising:
 providing PBI having imidazole nitrogens; 
 reacting the PBI with a compound containing a carbonyl group; and 
 substituting at least 85% of the imidazole nitrogens with a moiety from the compound, the substituted imidazole nitrogens being bonded to carbon of the carbonyl group. 
 
     
     
       2. The method of  claim 1  wherein the PBI comprises poly-2,2′(m-phenylene)-5,5′-bibenzimidazole. 
     
     
       3. The method of  claim 1  wherein the PBI is provided in a less than 5 wt % solution of the PBI in a solvent. 
     
     
       4. The method of  claim 1  further comprising ionizing the imidazole nitrogens before the reacting. 
     
     
       5. The method of  claim 4  wherein the ionizing comprises deprotonating with an alkali hydride. 
     
     
       6. The method of  claim 4  wherein the ionizing, reacting, and substituting occur at from about 20 to about 30° C. 
     
     
       7. The method of  claim 4  wherein the ionizing, reacting, and substituting occur at about atmospheric pressure. 
     
     
       8. The method of  claim 1  wherein the reacting uses more than 5 equivalents of the compound in relation to the imidazole nitrogens to be substituted. 
     
     
       9. The method of  claim 1  wherein substantially all of the imidazole nitrogens are substituted with the moiety. 
     
     
       10. The method of  claim 1  wherein the compound comprises RCOX, where R is organic, optionally containing an inorganic component, and X is a leaving group. 
     
     
       11. The method of  claim 10  wherein R comprises alkyl, aryl, alkenyl, or alkynyl and the inorganic component comprises oxygen, nitrogen, scandium, yttrium, titanium, zirconium, hafnium, vanadium, niobium, molybdenum, tungsten, iron, ruthenium, cobalt, rhodium, nickel, palladium, platinum, boron, aluminum, gallium, indium, silicon, germanium, tin, phosphorus, arsenic, antimony, sulfur, selenium, tellurium, or oxides thereof. 
     
     
       12. The method of  claim 10  wherein R consists of alkoxy or haloalkyl. 
     
     
       13. The method of  claim 10  wherein X comprises halogen, cyano, thiocyano, oxycyano, thioalkyl, alkoxy, fluoroalkoxy, sulfonylalkyl, oxyaromatic, thioaromatic, sulfonylaromatic, aromatic and alkyl carbodiimides, N-hydroxysuccinimide, oxyphosphorus containing compounds, or oxysilane containing compounds. 
     
     
       14. The method of  claim 1  wherein the compound comprises at least one of (CH 3 ) 2 CHCH 2 OCOCl, CH 3 CH 2 OCOCl, and BrCH 2 (CH 2 ) 3 COCl. 
     
     
       15. A substituted PBI synthesis method comprising:
 providing PBI having imidazole nitrogens; 
 reacting the PBI with a RCOX compound, where R is organic, optionally containing an inorganic component, and X is a leaving group; and 
 substituting at least a portion of the imidazole nitrogens with a RCO— moiety from the compound, the substituted imidazole nitrogens being bonded to the carbon of the RCO— moiety carbonyl group and R being bonded to the carbon of the carbonyl group by other than a C—O bond. 
 
     
     
       16. The method of  claim 15  further comprising ionizing the imidazole nitrogens before the reacting. 
     
     
       17. The method of  claim 16  wherein the ionizing comprises deprotonating with an alkali hydride. 
     
     
       18. The method of  claim 15  wherein the reacting uses more than 5 equivalents of the compound in relation to the imidazole nitrogens to be substituted. 
     
     
       19. The method of  claim 15  wherein substantially all of the imidazole nitrogens are substituted with the moiety. 
     
     
       20. The method of  claim 15  wherein R is bonded to the carbon of the carbonyl group by a C—C bond. 
     
     
       21. The method of  claim 20  wherein R is haloalkyl and X is halogen. 
     
     
       22. The method of  claim 15  wherein the compound comprises BrCH 2 (CH 2 ) 3 COCl. 
     
     
       23. A polymeric medium fabrication method comprising:
 providing PBI having imidazole nitrogens; 
 reacting the PBI with a compound containing a carbonyl group; 
 substituting at least 85% of the imidazole nitrogens with a moiety from the compound, the substituted imidazole nitrogens being bonded to carbon of the carbonyl group; and 
 forming a polymeric medium that comprises the substituted PBI. 
 
     
     
       24. The method of  claim 23  wherein the polymeric medium comprises a separatory medium. 
     
     
       25. The method of  claim 24  wherein the separatory medium exhibits an H 2 , Ar, N 2 , O 2 , CH 3 , or CO 2  gas permeability greater than the gas permeability of a comparable separatory medium instead comprising the PBI. 
     
     
       26. The method of  claim 23  wherein the polymeric medium comprises an electronically conductive medium. 
     
     
       27. The method of  claim 23  wherein the polymeric medium comprises an ionically conductive medium. 
     
     
       28. The method of  claim 23  wherein the PBI comprises poly-2,2′(m-phenylene)-5,5′-bibenzimidazole. 
     
     
       29. The method of  claim 23  further comprising deprotonating the imidazole nitrogens at from about 20 to about 30° C. in a less than 5 wt % solution of the PBI in a solvent. 
     
     
       30. The method of  claim 23  wherein the reacting and substituting occur at from about 20 to about 30° C. 
     
     
       31. The method of  claim 23  wherein the reacting uses at least 10 equivalents of the compound in relation to the imidazole nitrogens to be substituted. 
     
     
       32. The method of  claim 23  wherein substantially all of the imidazole nitrogens are substituted with the moiety. 
     
     
       33. The method of  claim 23  wherein the compound comprises RCOX, where R is organic, optionally containing an inorganic component, and X is a leaving group. 
     
     
       34. The method of  claim 33  wherein R comprises alkyl, aryl, alkenyl, or alkynyl and the inorganic component comprises oxygen, nitrogen, scandium, yttrium, titanium, zirconium, hafnium, vanadium, niobium, molybdenum, tungsten, iron, ruthenium, cobalt, rhodium, nickel, palladium, platinum, boron, aluminum, gallium, indium, silicon, germanium, tin, phosphorus, arsenic, antimony, sulfur, selenium, tellurium, or oxides thereof. 
     
     
       35. The method of  claim 33  wherein R consists of alkoxy or haloalkyl. 
     
     
       36. The method of  claim 33  wherein X comprises halogen, cyano, thiocyano, oxycyano, thioalkyl, alkoxy, fluoroalkoxy, sulfonylalkyl, oxyaromatic, thioaromatic, sulfonylaromatic, aromatic and alkyl carbodiimides, N-hydroxysuccinimide, oxyphosphorus containing compounds, or oxysilane containing compounds. 
     
     
       37. The method of  claim 23  wherein the compound comprises at least one of (CH 3 ) 2 CHCH 2 OCOCl, CH 3 CH 2 OCOCl, and BrCH 2 (CH 2 ) 3 COCl. 
     
     
       38. The method of  claim 23  wherein the substituted PBI exhibits a first temperature marking an onset of weight loss coffesponding to reversion of the substituted PBI, the first temperature being less than a second temperature marking an onset of decomposition of an otherwise identical PBI compound without the substituted moiety, and forming the polymeric medium comprises heating treating the polymeric medium and removing the substituted moiety from the PBI. 
     
     
       39. A polymeric medium fabrication method comprising:
 providing PBI having imidazole nitrogens; 
 reacting the PBI with a RCOX compound, where R is organic, optionally containing an inorganic component, and X is a leaving group; 
 substituting at least a portion of the imidazole nitrogens with a RCO— moiety from the compound, the substituted imidazole nitrogens being bonded to carbon of the RCO— moiety carbonyl group and R being bonded to the carbon of the carbonyl group by other than a C—O bond; and 
 forming a polymeric medium that comprises the substituted PBI. 
 
     
     
       40. The method of  claim 39  wherein the polymeric medium comprises a separatory medium. 
     
     
       41. The method of  claim 39  wherein the polymeric medium comprises an electronically conductive medium. 
     
     
       42. The method of  claim 39  wherein the polymeric medium comprises an ionically conductive medium. 
     
     
       43. The method of  claim 39  further comprising deprotonating the imidazole nitrogens at from about 20 to about 30° C. in a less than 5 wt % solution of the PBI in a solvent. 
     
     
       44. The method of  claim 39  wherein the reacting uses at least 10 equivalents of the compound in relation to the imidazole nitrogens to be substituted. 
     
     
       45. The method of  claim 39  wherein substantially all of the imidazole nitrogens are substituted with the RCO— moiety. 
     
     
       46. The method of  claim 39  wherein R is bonded to the carbon of the carbonyl group by a C—C bond. 
     
     
       47. The method of  claim 46  wherein R is haloalkyl and X is halogen. 
     
     
       48. The method of  claim 39  wherein the compound comprises BrCH 2 (CH 2 ) 3 COCl.